The US today recalled its ambassador to Syria in the aftermath of yesterday's assassination of former Lebanese prime minister Rafik Hariri in Beirut.

The departure of the ambassador, Margaret Scobey, is another sign of growing US displeasure with Syria over its continued military presence and political influence in Lebanon.

The US yesterday condemned the massive blast on Beirut's seafront that killed at least 15 people, including Mr Hariri, and injured 120 others. The US administration insisted that Syria comply with a UN resolution calling for the withdrawal of Syrian troops from Lebanon.

The White House said it was consulting with the UN security council about taking punitive measures against those responsible for the killing in Beirut.

State department spokesman Richard Boucher said Mr Bush had summoned Ms Scobey back to the US for "urgent consultations".

"It's too early to know who was responsible for this attack," White House spokesman Scott McClellan told reporters, but he added: "Syria's presence in Lebanon is a destabilising force. The terrorist attack further underscores the importance of letting the Lebanese people control their future."

Though there has been one claim of responsibility for the blast, officials have been careful to stress that they do not yet know who is behind the bombing. However the Lebanese government said the investigation suggested a suicide bomber had carried out the attack.

The interior minister, Suleiman Frenjieh, told a news conference today: "The security services are almost certain that it was a suicide car bomb."